Empirical Study of Ne in H-Mode Pedestal in DIII-D (open access)

Empirical Study of Ne in H-Mode Pedestal in DIII-D

There is compelling empirical [1] and theoretical [2] evidence that the global confinement of H-mode discharges increases as the pedestal pressure or temperature increases. Therefore, confidence in the performance of future machines requires an ability to predict the pedestal conditions in those machines. At this time, both the theoretical and empirical understanding of transport in the pedestal are incomplete and are inadequate to predict pedestal conditions in present or future machines. Recent empirical results might be evidence of a fundamental relation between the electron temperature T{sub e} and electron density n{sub e} profiles in the pedestal. A data set from the ASDEX-Upgrade tokamak has shown that {eta}{sub e}, the ratio between the scale lengths of the n{sub e} and T{sub e} profiles, exhibits a value of about 2 throughout the pedestal, despite a large range of the actual density and temperature values [3]. Data from the DIII-D tokamak show that over a wide range of pedestal density, the width of the steep gradient region for the T{sub e} profile is about 1-2 times the corresponding width for the n{sub e} profile, where both widths are measured from the plasma edge [4]. Thus, the barrier in the density might form a …
Date: May 5, 2005
Creator: . Groebner, R. J.; Osborne, T. H.; Fenstermacher, M. E.; Leonard, A. W.; Mahdavi, M. A.; Snyder, P. B. et al.
Object Type: Article
System: The UNT Digital Library
Systematics of Fission-Product Yields (open access)

Systematics of Fission-Product Yields

None
Date: May 5, 2002
Creator: A.C.Wahl
Object Type: Report
System: The UNT Digital Library
Variability of Ocean Heat Uptake: Reconciling Observations and Models (open access)

Variability of Ocean Heat Uptake: Reconciling Observations and Models

This study examines the temporal variability of ocean heat uptake in observations and in climate models. Previous work suggests that coupled Atmosphere-Ocean General Circulation Models (A-OGCMs) may have underestimated the observed natural variability of ocean heat content, particularly on decadal and longer timescales. To address this issue, we rely on observed estimates of heat content from the 2004 World Ocean Atlas (WOA-2004) compiled by Levitus et al. (2005). Given information about the distribution of observations in WOA-2004, we evaluate the effects of sparse observational coverage and the infilling that Levitus et al. use to produce the spatially-complete temperature fields required to compute heat content variations. We first show that in ocean basins with limited observational coverage, there are important differences between ocean temperature variability estimated from observed and infilled portions of the basin. We then employ data from control simulations performed with eight different A-OGCMs as a test-bed for studying the effects of sparse, space- and time-varying observational coverage. Subsampling model data with actual observational coverage has a large impact on the inferred temperature variability in the top 300 and 3000 meters of the ocean. This arises from changes in both sampling depth and in the geographical areas sampled. Our …
Date: May 5, 2005
Creator: AchutaRao, K. M.; Santer, B. D.; Gleckler, P. J.; Taylor, K.; Pierce, D.; Barnett, T. et al.
Object Type: Article
System: The UNT Digital Library
Tank Characterization Report for Single Shell Tank (SST) 241-TX-118 (open access)

Tank Characterization Report for Single Shell Tank (SST) 241-TX-118

None
Date: May 5, 2000
Creator: Adams, M. R.
Object Type: Report
System: The UNT Digital Library
An Integrated Hydrologic Bayesian Multi-Model Combination Framework: Confronting Input, parameter and model structural uncertainty in Hydrologic Prediction (open access)

An Integrated Hydrologic Bayesian Multi-Model Combination Framework: Confronting Input, parameter and model structural uncertainty in Hydrologic Prediction

This paper presents a new technique--Integrated Bayesian Uncertainty Estimator (IBUNE) to account for the major uncertainties of hydrologic rainfall-runoff predictions explicitly. The uncertainties from the input (forcing) data--mainly the precipitation observations and from the model parameters are reduced through a Monte Carlo Markov Chain (MCMC) scheme named Shuffled Complex Evolution Metropolis (SCEM) algorithm which has been extended to include a precipitation error model. Afterwards, the Bayesian Model Averaging (BMA) scheme is employed to further improve the prediction skill and uncertainty estimation using multiple model output. A series of case studies using three rainfall-runoff models to predict the streamflow in the Leaf River basin, Mississippi are used to examine the necessity and usefulness of this technique. The results suggests that ignoring either input forcings error or model structural uncertainty will lead to unrealistic model simulations and their associated uncertainty bounds which does not consistently capture and represent the real-world behavior of the watershed.
Date: May 5, 2006
Creator: Ajami, N. K.; Duan, Q. & Sorooshian, S.
Object Type: Article
System: The UNT Digital Library
FACT (Version 2.0) - Subsurface Flow and Contaminant Transport Documentation and User's Guide (open access)

FACT (Version 2.0) - Subsurface Flow and Contaminant Transport Documentation and User's Guide

This report documents a finite element code designed to model subsurface flow and contaminant transport, named FACT. FACT is a transient three-dimensional, finite element code designed to simulate isothermal groundwater flow, moisture movement, and solute transport in variably saturated and fully saturated subsurface porous media.
Date: May 5, 2000
Creator: Aleman, S. E.
Object Type: Report
System: The UNT Digital Library
Crack growth rates and metallographic examinations of Alloy 600 and Alloy 82/182 from field components and laboratory materials tested in PWR environments. (open access)

Crack growth rates and metallographic examinations of Alloy 600 and Alloy 82/182 from field components and laboratory materials tested in PWR environments.

In light water reactors, components made of nickel-base alloys are susceptible to environmentally assisted cracking. This report summarizes the crack growth rate results and related metallography for field and laboratory-procured Alloy 600 and its weld alloys tested in pressurized water reactor (PWR) environments. The report also presents crack growth rate (CGR) results for a shielded-metal-arc weld of Alloy 182 in a simulated PWR environment as a function of temperature between 290 C and 350 C. These data were used to determine the activation energy for crack growth in Alloy 182 welds. The tests were performed by measuring the changes in the stress corrosion CGR as the temperatures were varied during the test. The difference in electrochemical potential between the specimen and the Ni/NiO line was maintained constant at each temperature by adjusting the hydrogen overpressure on the water supply tank. The CGR data as a function of temperature yielded activation energies of 252 kJ/mol for a double-J weld and 189 kJ/mol for a deep-groove weld. These values are in good agreement with the data reported in the literature. The data reported here and those in the literature suggest that the average activation energy for Alloy 182 welds is on the …
Date: May 5, 2008
Creator: Alexandreanu, B.; Chopra, O. K. & Shack, W. J.
Object Type: Report
System: The UNT Digital Library
Poland petroleum refinery sludge lagoon demonstration project (open access)

Poland petroleum refinery sludge lagoon demonstration project

The US Department of Energy and the Institute for Ecology of Industrial Area have been working together to develop mutually beneficial, cost-effective environmental remediation technologies such as the demonstration of bioremediation techniques for the clean up of acidic petroleum sludge impacted soils at an oil refinery in southern Poland. After an expedited site characterization, treatability study, and a risk assessment study, a remediation strategy was devised. The waste material was composed primarily of high molecular weight paraffinic and polynuclear aromatic hydrocarbons. A biopile design which employed a combination of passive and active aeration in conjunction with nutrient and surfactant application as used to increase the biodegradation of the contaminants of concern.
Date: May 5, 2000
Creator: Altman, D. J.
Object Type: Article
System: The UNT Digital Library
Congressional Record: Its Production, Distribution, and Accessibility (open access)

Congressional Record: Its Production, Distribution, and Accessibility

This report provides information about the Production, Distribution, and Accessibility of Congressional Record. The Congressional Record is the most widely published account of the debates and activities in congress.
Date: May 5, 2008
Creator: Amer, Mildred
Object Type: Report
System: The UNT Digital Library
Electrochromically switched, gas-reservoir metal hydride devices with application to energy-efficient windows (open access)

Electrochromically switched, gas-reservoir metal hydride devices with application to energy-efficient windows

Proof-of-principle gas-reservoir MnNiMg electrochromic mirror devices have been investigated. In contrast to conventional electrochromic approaches, hydrogen is stored (at low concentration) in the gas volume between glass panes of the insulated glass units (IGUs). The elimination of a solid state ion storage layer simplifies the layer stack, enhances overall transmission, and reduces cost. The cyclic switching properties were demonstrated and system durability improved with the incorporation a thin Zr barrier layer between the MnNiMg layer and the Pd catalyst. Addition of 9 percent silver to the palladium catalyst further improved system durability. About 100 full cycles have been demonstrated before devices slow considerably. Degradation of device performance appears to be related to Pd catalyst mobility, rather than delamination or metal layer oxidation issues originally presumed likely to present significant challenges.
Date: May 5, 2008
Creator: Anders, Andre; Slack, Jonathan L. & Richardson, Thomas J.
Object Type: Article
System: The UNT Digital Library
Nanotube-based gas sensors - role of structural defects (open access)

Nanotube-based gas sensors - role of structural defects

Existing theoretical literature suggests that defect-free, pristine carbon nanotubes (CNTs) interact weakly with many gas molecules like H{sub 2}O, CO, NH{sub 3}, H{sub 2}, and so on. The case of NH{sub 3} is particularly intriguing because this is in disagreement with experimentally observed changes in electrical conductance of CNTs upon exposure to these gases. In order to explain such discrepancy, we have carried out Density Functional Theory (DFT) investigations of the role of common atomistic defects in CNT (Stone-Wales, monovacancy, and interstitial) on the chemisorption of NH{sub 3}. Computed binding energies, charge transfer, dissociation barriers, and vibrational modes are compared with existing experimental results on electrical conductance, thermal desorption and infrared spectroscopy.
Date: May 5, 2005
Creator: Andzelm, J; Govind, N & Maiti, A
Object Type: Article
System: The UNT Digital Library
Women in Iraq: Background and Issues for U.S. Policy (open access)

Women in Iraq: Background and Issues for U.S. Policy

The issue of women’s rights in Iraq has taken on new relevance, following the U.S.-led invasion of Iraq in 2003, efforts to reconstruct Iraq, and recent elections for a Transitional National Assembly (TNA). Over the past three years, the Bush Administration has reiterated its interest in ensuring that Iraqi women participate in politics and ongoing reconstruction efforts in Iraq. There has also been a widening debate regarding the extent to which the U.S.-led reconstruction efforts have been able to enhance women’s rights in Iraq and encourage their participation in Iraq’s governing institutions.
Date: May 5, 2004
Creator: Armanios, Febe
Object Type: Report
System: The UNT Digital Library
Atmospheric Radiation Measurement Program Facilities Newsletter, April 2000 (open access)

Atmospheric Radiation Measurement Program Facilities Newsletter, April 2000

Monthly newsletter discussing news and activities related to the Atmospheric Radiation Measurement Program, articles about weather and atmospheric phenomena, and other related topics.
Date: May 5, 2000
Creator: Atmospheric Radiation Measurement Program (U.S.)
Object Type: Journal/Magazine/Newsletter
System: The UNT Digital Library
Search for B Meson Decays to eta' eta' K (open access)

Search for B Meson Decays to eta' eta' K

The authors describe searches for decays of B mesons to the charmless final states {eta}'{eta}'K. The data consist of 228 million B{bar B} pairs produced in e{sup +}e{sup -} annihilation, collected with the BABAR detector at the Stanford Linear Accelerator Center. The 90% confidence level upper limits for the branching fractions are {Beta}(B{sup 0} {yields} {eta}'{eta}'K{sup 0}) < 31 x 10{sup -6} and {Beta}(B{sup +} {yields} {eta}'{eta}'K{sup +}) < 25 x 10{sup -6}.
Date: May 5, 2006
Creator: Aubert, B.
Object Type: Report
System: The UNT Digital Library
Disaster Mitigation Assistance Bills in the 106th Congress: Comparison of Provisions (open access)

Disaster Mitigation Assistance Bills in the 106th Congress: Comparison of Provisions

The Administration initiative to shift federal emergency management policy away from a "response and recovery" emphasis has generated little congressional controversy, although some have raised concerns about the cost effectiveness of implementing a mitigation strategy. Greater attention, it is generally argued, should be given to mitigation (loss reduction) efforts before disasters occur in order to reduce future losses. Legislation (H.R. 707, S. 1691) pending before the 106th Congress would amend the Robert T. Stafford Disaster Relief and Emergency Assistance Act (the Stafford Act) which authorizes federal assistance when the President declares that a catastrophe has overwhelmed state and local resources.
Date: May 5, 2000
Creator: Bea, Keith
Object Type: Report
System: The UNT Digital Library
Application of Reservoir Characterization and Advanced Technology to Improve Recovery and Economics in a Lower Quality Shallow Shelf San Andres Reservoir. Annual Report: August 3, 2000--August 2, 2001 (open access)

Application of Reservoir Characterization and Advanced Technology to Improve Recovery and Economics in a Lower Quality Shallow Shelf San Andres Reservoir. Annual Report: August 3, 2000--August 2, 2001

The OXY-operated Class 2 Project at West Welch is designed to demonstrate how the use of advanced technology can improve the economics of miscible CO{sub 2} injection projects in lower quality Shallow Shelf Carbonate reservoirs. The research and design phase (Budget Period 1) primarily involved advanced reservoir characterization. The current demonstration phase (Budget Period 2) is the implementation of the reservoir management plan for an optimum miscible CO{sub 2} flood design based on the reservoir characterization. Although Budget Period 1 for the Project officially ended 12/31/96, reservoir characterization and simulation work continued during the Budget Period 2. During the seventh annual reporting period (8/3/00-8/2/01) covered by this report, work continued on interpretation of the interwell seismic data to create porosity and permeability profiles which were distributed into the reservoir geostatistically. The initial interwell seismic CO{sub 2} monitor survey was conducted and the acquired data processed and interpretation started. Only limited well work and facility construction were conducted in the project area. The CO{sub 2} injection initiated in October 1997 was continued, although the operator had to modify the operating plan in response to low injection rates, well performance and changes in CO{sub 2} supply. CO{sub 2} injection was focused in …
Date: May 5, 2003
Creator: Beebe, Tom
Object Type: Report
System: The UNT Digital Library
FY2005 Supplemental Appropriations for Iraq and Afghanistan, Tsunami Relief, and Other Activities (open access)

FY2005 Supplemental Appropriations for Iraq and Afghanistan, Tsunami Relief, and Other Activities

This report presents Supplemental Appropriations for Iraq and Afghanistan, Tsunami Relief, and other activities for FY2005.
Date: May 5, 2005
Creator: Belasco, Amy & Nowels, Larry
Object Type: Report
System: The UNT Digital Library
Supplemental Appropriations FY2003: Iraq Conflict, Afghanistan, Global War on Terrorism, and Homeland Security (open access)

Supplemental Appropriations FY2003: Iraq Conflict, Afghanistan, Global War on Terrorism, and Homeland Security

None
Date: May 5, 2003
Creator: Belasco, Amy & Nowels, Larry
Object Type: Report
System: The UNT Digital Library
Military Medical Care Services: Questions and Answers (open access)

Military Medical Care Services: Questions and Answers

None
Date: May 5, 2005
Creator: Best, Richard A., Jr.
Object Type: Report
System: The UNT Digital Library
The Power of a Good Idea: Quantitative Modeling of the Spread of Ideas from Epidemiological Models (open access)

The Power of a Good Idea: Quantitative Modeling of the Spread of Ideas from Epidemiological Models

The population dynamics underlying the diffusion of ideas hold many qualitative similarities to those involved in the spread of infections. In spite of much suggestive evidence this analogy is hardly ever quantified in useful ways. The standard benefit of modeling epidemics is the ability to estimate quantitatively population average parameters, such as interpersonal contact rates, incubation times, duration of infectious periods, etc. In most cases such quantities generalize naturally to the spread of ideas and provide a simple means of quantifying sociological and behavioral patterns. Here we apply several paradigmatic models of epidemics to empirical data on the advent and spread of Feynman diagrams through the theoretical physics communities of the USA, Japan, and the USSR in the period immediately after World War II. This test case has the advantage of having been studied historically in great detail, which allows validation of our results. We estimate the effectiveness of adoption of the idea in the three communities and find values for parameters reflecting both intentional social organization and long lifetimes for the idea. These features are probably general characteristics of the spread of ideas, but not of common epidemics.
Date: May 5, 2005
Creator: Bettencourt, L. M. A.; Cintron-Arias, A.; Kaiser, D. I. & Castillo-Chavez, C.
Object Type: Report
System: The UNT Digital Library
A texture-based framework for improving CFD data visualization in a virtual environment (open access)

A texture-based framework for improving CFD data visualization in a virtual environment

In the field of computational fluid dynamics (CFD) accurate representations of fluid phenomena can be simulated hut require large amounts of data to represent the flow domain. Most datasets generated from a CFD simulation can be coarse, {approx}10,000 nodes or cells, or very fine with node counts on the order of 1,000,000. A typical dataset solution can also contain multiple solutions for each node, pertaining to various properties of the flow at a particular node. Scalar properties such as density, temperature, pressure, and velocity magnitude are properties that are typically calculated and stored in a dataset solution. Solutions are not limited to just scalar properties. Vector quantities, such as velocity, are also often calculated and stored for a CFD simulation. Accessing all of this data efficiently during runtime is a key problem for visualization in an interactive application. Understanding simulation solutions requires a post-processing tool to convert the data into something more meaningful. Ideally, the application would present an interactive visual representation of the numerical data for any dataset that was simulated while maintaining the accuracy of the calculated solution. Most CFD applications currently sacrifice interactivity for accuracy, yielding highly detailed flow descriptions hut limiting interaction for investigating the field.
Date: May 5, 2005
Creator: Bivins, Gerrick O'Ron
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Drilling, Sampling, and Well-Installation Plan for the IFC Well Field, 300 Area (open access)

Drilling, Sampling, and Well-Installation Plan for the IFC Well Field, 300 Area

The 300 Area was selected as a location for an IFC because it offers excellent opportunities for field research on the influence of mass-transfer processes on uranium in the vadose zone and groundwater. The 300 Area was the location of nuclear fuel fabrication facilities and has more than 100 waste sites. Two of these waste sites, the North and South Process Ponds received large volumes of process waste from 1943 to 1975 and are thought to represent a significant source of the groundwater uranium plume in the 300 Area. Geophysical surveys and other characterization efforts have led to selection of the South Process Pond for the IFC.
Date: May 5, 2008
Creator: Bjornstad, Bruce N. & Horner, Jacob A.
Object Type: Report
System: The UNT Digital Library

Why Evolutionary Biology and Genome Sciences Need Each Other

None
Date: May 5, 2005
Creator: Boore, Jeffrey
Object Type: Presentation
System: The UNT Digital Library
An Overview of the Administration's Strengthening America's Communities Initiative (open access)

An Overview of the Administration's Strengthening America's Communities Initiative

This report discusses administration’s proposed base program called strengthening America’s communities initiative intended to award funds in support of job creation and economic development.
Date: May 5, 2005
Creator: Boyd, Eugene; Mulock, Bruce K.; Smale, Pauline; Cowan, Tadlock; Laney, Garrine P. & Foote, Bruce E.
Object Type: Report
System: The UNT Digital Library